Gelatin relief



Nov. 28, 1939. M. HERBST Er A1. i 2,181,485

GELATIN RELIEF l Filed May 11, 1938 Ffa 3 HBSOlPf/ah CHRI/i 0f ADDED Pyf JENJITIV/TY CURKE 0F SEALS/T1251) EMULS/01V 4 I l l I l 700 650 j; 600 550 00l 21 450 E 400 35001;/

Patented Nov. 28, 1939 UNITED STATES PATENT OFFICE mim GELA'HNBELIEI' Max Herbst, Mannheim-Rheinau, and

hankenburger, Ludwigshafen, Germany allignor, by meme assignments, to Agfa Anloo Corporation, Binghamton, N. Y., a corporation of Delaware Application May 11, .1

Y In Germany 938, Serial No. 207m May 13. 193'!v 8 Claims. (Cl. ils-5.6) v

produced by dyeing the sensitized emulsion complementarily only to a part of the sensitizing region. By fsensitizing region is to be understood the region of the wave lengths of the spec- 15 tral sensitivity diminished by that of the natural sensitivity of the non-sensitizedl emulsion, that is to say that spectral region in which the sensitivity natural to the non-sensitized silver halide emulsion is increased by the sensitizing. Itfol- 20 lows that, for example, yellow or orange dyeings, such as are used in the duplicating lms and the like or for damping the blue sensitivity, that is to say the natural sensitivity of the silver halide, are not within this invention.

I Further objects of the invention will appear from the following description. *f'

Reference is made to the accompanying diagrams 1 to 4 which illustrate the invention for diiferent spectral regions. y

n The advantage of a dyeing which is only in part complementary consists especially in an essential increase of general sensitivity. Any dyeing which absorbs light in the region ofl the sensitivity of the silver halide'to light diminishes the sensitivity on purely optical grounds; by a narrow spectral limitation of the dyeing, however, this loss of sensitivity is diminished, On the other hand, since it has been found that wholly undyed silver halide layers yield objectionably a hard reliefs, it was unexpected 'that a dyeing.

only violet, blue and green of short wave length,

that is to say is only complementary to the natural sensitivity of the silver halide, is practically o ineifective in respect of improving gradatlon of the etching. f

It is advantageous to use such colorings as have an increasing absorption capacity towards-the' long wave lengths starting from 540 ma or still u longer, since it is plau'ticularlyv the light of the-`V v long wave length that produces gradation for etched reliefs.

The following examples illustrate the invention but they are not intended to limit it thereto:

1. A silver bromide emulsion, the sensitivity 5 curve of which towards the long wave lengths extends to l480 ma (A in Figure 1) is sensitized orthochromatically so that its sensitivity now extends to 600 mp (as indicatedat B). The region between A and B'corresponds with the sensitizl() ing region. In order to make this sensitized emulsion suitable for etched reliefs, it is mixed with a blue-green dye, for instance, Fanalbremerblau (cf. Schultz, Farbstoiftabellen, '7th edit., vol. I, 1931, No. 826) the light absorption curve l5 of whichbegins at 530 ma (as indicated at C) and increases towards the long wave lengths.

2. A panchromatically sensitized silver halide emulsion the sensitivity of which is`represented by the curve I shown in Figure 2 is made useful 20 .for etched reliefs byV mixing'it with a finely dispersed colorless solid substanceof which the main part has a particle diameter not exceeding l n which substance does not influence the silver halide and is insoluble in the photographic treat- 25 ing baths, and with a blue-green dyestuff, (for sorption curve of which starts from 500 ma (C) and extends to any point above 520 ma.

4. An orthochromatically sensitized silver hal- 40 ide gelatin emulsion the sensitivity curve of which extends to 6,20 mu (sensitizing region AB, cf. Figure 4) is coloredwith a dye (cinnabar, for instance) the luminous absorption capacity of which begins in the long wave range at 600 ma `i5 (G) and extends towards the short wave lengths up to any points, for instance 500 ma (C), 42 mp. (E) or still further` (F).

For obtaining gelatin reliefs for printing the emulsion layers as above described are exposed 50 to light, developed by the usual method without tanning Aand fixed. The relief is produced by v etchingwith a solution ofh'ydrogenperoxide (cf. .Wall, The History of-Three-Color Photography,

1925. page 857).

f photographic treating baths, sensitizing said silver ceeding 1 p. which substance does not affect the silver halide and is insoluble in the photographic treating baths, sensitizing said silver halide emul- A sion for a spectral region diierent from its initial sensitivity, dyeing said silver halide emulsion in a color complementary only to a partof said spectral region, casting said emulsion on a support to form a layer, producing a latent image in said layer, developing said image to a silver picture, and etching said layer to form a relief.

2. A process of producing a gelatin relief for printing. which comprises incorporating in a silver halide gelatin emulsion a solid substance of which the main part has a particle diameter not exceeding 1 a which substance does not affect the silver halide and is insoluble in the photographic treating baths, sensitizing said silver halide emul Y sion panchromatically, mixing said silver halide emulsion with a dyestuif the light absorption curve of which embraces the region between 570 and 700 mi, casting said emulsion on a support to form a layer, producing a latent image in said layer, developing said image to a silver picture, and etching said layer to form a relief.

3. A process of producing a gelatin relief for printing which comprises incorporating in a silver halide gelatin emulsion a solid substance of which the main part has a particle diameter not exceeding 1 a which substance does not aiect the silver halide and is insoluble in the halide emulsion orthochromatically, mixing said silver halide emulsion Witha dyestuif the light absorption curve of which begins at 530 ma and increases towards the long wave lengths,

' casting said emulsion on a support to form a layer, producing a latent image in said layer, developing said image to a silver picture, and etching said layer to form a relief.

4. A process of producing a gelatin relief for printing which comprises incorporating in a silver halide gelatin emulsion a solid substance of which the main part has a particle diameter not exceeding 1 a which substance does not aiect the silver halide and is insoluble in the photographic treating baths, sensitizing said silver halide emulsion orthochromatically, mixing said silver halide emulsion with a dyestuff the light absorption curve of which begins in the long-Wave region at 600 mp and extends'towards the short wave lengths up to any point, casting said emulsion on a support to form a layer, producing a latent image in said layer, developing said image to a silver picture, and etching said layer to form a relief.

5. A photographic material which comprises a support and attached to said support a silver halide gelatin emulsion layer containing a solid substance of which the main part has a particle diameter not exceeding 1 p. which substance does not affect the silver 4halide and is insoluble in the photographic treating baths, said emulsion layer being sensitized for a spectral region different from its initial sensitivity and being colored only with a dyestuft' of a color complementary only to a part of said spectral region.

6. A photographic material which comprises y a support and attached to said support a silver halide gelatin emulsion layer containing a solid substance of which the main part has a particle diameter not exceeding 1 a which substance does not affect the silver halide and is insoluble in the photographic treating baths, said emulsion layer being sensitized panchromatically and being colored only with a dyestuff the light absorption curve of which embraces the region between 570 and r ma.

7. A photographic material which comprises a support and attached to said support a silver halide gelatin emulsion layer containing a solid substance of which the main part has a particle diameter not exceeding 1 p. which substance does not affect the silver halide and is insoluble in the photographic treating baths, said emulsion layer being sensitized orthochromatically and being colored only with a dyestuff the light absorption curve of which begins at 530 me and increases towards the long wave lengths.

8. A photographic material which comprises a support and attached to said support a silver halide gelatin emulsion layer containing a solid substance of which the-main part has a particle diameter not exceeding 1 p. which substance does not affect the silver halide and is insoluble in the photographic treating baths, said emulsion layer being sensitized orthochromatically and being colored only with a dyestuff the light absorption curve of which begins in the long-Wave region at 600 ma and extends towards the short wave lengths up to any point. 

